Various systems have been proposed to provide security against unauthorized opening of a door leading to dwelling interiors such as houses, apartments, hotel rooms and the like. Such systems have incorporated devices to be placed against the door in a temporary and easily removable configuration. U.S. Pat. Nos. 4,300,796 to Lane and 4,483,558 to Van Meter, disclose door security devices of the type which engage the door at the door knob or immediately below the door knob and extend from there down to the floor at an acute angle. These systems are formed of elongated rod like or tubular members in a telescoping relationship. As disclosed in the patent to Van Meter, the security device has a rotatable floor engaging shoe fitted on one side with a skid pad having a relatively high coefficient of friction, e.g. formed of rubber or a rubber-like plastic, for use on smooth floor surfaces and on the other side a plurality of downwardly projecting teeth which are adapted to penetrate into and engage a carpet. Devices of this nature are necessarily somewhat bulky and unwieldy.
Another approach which involves a relatively compact device is disclosed in U.S. Pat. No. 4,585,259 to Vidas. The Vidas device takes the form of a base member having a door abutting member at one end and a door frame engaging member at the other end. Intermediate of the door abutting and frame engaging members is an upright support member which carries a threaded stopper so that the door can be interposed between the abutting face of the abutting member and the stopper. The upright support member is also provided with foot members which extend downwardly from the upright support to engage the floor in the event the frame engaging member is not operative. A substantially simpler arrangement is disclosed in U.S. Pat. No. 4,890,092 to Grimm. The Grimm device incorporates a wedge shaped housing which is adapted to be forced underneath the lower edge of the door. The tapered surface of the wedge incorporates a switch for an audible alarm at the rear wall of the housing. Various inserts having traction projections for frictional engagement with smooth surfaces or hooked-shaped fasteners for fabric surfaces may be incorporated at the bottom of the housing. In the event of an unauthorized opening of the door, the switch is depressed to complete a circuit through a battery in the housing and the alarm to sound the audible alarm signal.